This invention relates to a device or unit for mounting or attaching a camera unit to a camera attachment plate such as a door, which camera unit is designed to shoot or view a scene from one side of the door (referred to as the back) that is on the other side of the door (referred to as the front). More particularly, the invention relates to a mounting or attachment unit wherein the camera unit can be attached to any one of a variety of attachment plates of different plate thicknesses as the occasion may demand.
Such camera unit is sometimes referred to as a "doorscope camera" or "doorscope camera unit" in the present specification and may be a television camera for watching the outdoors.
Heretofore, when mounting the camera unit to a door or the like camera attachment plate, a through-hole is formed in the attachment plate, and the camera lens body tube member is inserted into the through-hole, while the camera part is disposed behind or on the one side of the plate.
Since a predetermined minimum length of the camera lens body tube is required as a function of the type of the optical system used, the thickness of the camera attachment plate should be less than the length of the camera lens body tube member. There will occasionally be a gap between the plate and the camera part upon setting the end part of the camera lens body tube in position on the front or on the other side of the plate.
When the thickness of the camera attachment plate is greater than the minimum length of the camera lens body tube member, an extension ring or rings are attached to the camera lens body tube member so that the length of the camera lens body tube member is greater than the thickness of the camera attachment plate. However, since the length of the extension ring itself is of a predetermined length, fine adjustment of the length of the camera lens body tube members to the thickness of the attachment plate is not necessarily feasible. Therefore, a gap may again exist between the attachment plate and the camera part upon setting the end part of the body tube in position on the other side of the plate.
Such a gap may cause the camera part to chatter while causing the body tube member to be injured under the weight of the camera part, since the camera part is held only by the camera lens body tube.
For overcoming such drawback, devices shown in FIGS. 1 and 2 are used for supporting the camera part at one side of the camera attachment plate.
In the device shown in FIG. 1, there is shown a camera part 30 and camera lens body tube member 32 with several plate-like shims 33 disposed within the gap between the camera part 30 and the inner surface of the camera attachment plate 31 so as to fill the gap to hold the camera part 30 without chattering.
In the device shown in FIG. 2, a U-shaped holder 42 is disposed inwardly of the camera attachment plate 41 for holding the camera part 40. Both sides of the holding member 42 are provided with two or more aligned throughholes 43 in which mating or matching projections on the camera part 41 are slidingly guided for adjustably positioning and mounting the camera part 40 in the holding member 42.
The device shown in FIG. 1 is inconvenient in that several plate-like shims 33 are required and, when attaching the camera unit to the attachment plate 31, the body tube should be passed through these shims to be clamped between the camera part 30 and the plate, so that difficulties are involved in the assembling operation.
The device shown in FIG. 2 is bulky and is not effective to reduce the size of the camera unit because the separate holding member 42 must be provided for holding and securing the camera part 40. Moreover, it is difficult to properly adjust the position of the projections 44 within the mating through-holes 43 in the holding member 42 from the inside of the plate 41 so as to hold the camera part 40 parallel to the surface of the plate 41.
In addition, since the force to prop or support an operating portion of the camera against the camera attachment plate is not achieved in the device shown in FIG. 1 or 2, the camera attachment unit is frequently unable to withstand the impact caused when the camera attachment plate is moved, for example, when the plate is a movable member such as a door.
These and other objects of this invention will become apparent from the following disclosure and appended claims.